530. Minimum Absolute Difference in BST

最新推荐文章于 2022-08-14 16:27:15 发布

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最新推荐文章于 2022-08-14 16:27:15 发布

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本文介绍了一种算法，用于找到二叉搜索树中任意两节点值之差的最小绝对值。通过中序遍历确保节点值有序，并计算相邻节点间的最小差值。

Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.

Example:

Input:

   1
    \
     3
    /
   2

Output:
1

Explanation:
The minimum absolute difference is 1, which is the difference between 2 and 1 (or between 2 and 3).

Note: There are at least two nodes in this BST.

求二叉搜索树任意两个节点值之差的最小值。

二叉搜索树的中序遍历是有序的，求相邻连两点之间差的最小值即可。程序如下所示：

/**
 * Definition for a binary tree node.
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
class Solution {
    private int min = Integer.MAX_VALUE;
    private Integer pre = null;
    public int getMinimumDifference(TreeNode root) {
        middleTraverse(root);
        return min;
    }
    public void middleTraverse(TreeNode root){
        if (root != null){
            middleTraverse(root.left);
            if (pre != null){
                min = Math.min(min, root.val - pre);
            }
            pre = root.val;
            middleTraverse(root.right);
        }
    }
}